Apparatus and Method to Configure Antenna Beam Width

ABSTRACT

Using High-beam and low-beam transmission signals that have different antenna tilts, different beam-widths, and different polarizations than one another may provide performance advantages in wireless networks. The high-beam transmission signal and the low-beam transmission signal may have orthogonal polarizations. For example, the high-beam transmission signal and the low-beam transmission signal may be linearly polarized signals having different electromagnetic field (E-field) polarization angles with respect to the y-axis, e.g., +/− forty-five degrees with respect to a vertically polarized wave. As another example, the high-beam transmission signal may be a vertically polarized signal, and the low-beam transmission signal may be a horizontally polarized signal, or vice-versa. In addition to having orthogonal polarizations, the low-beam transmission signal may have a greater antenna beam down-tilt angle, and a wider beam-width than the high-beam transmission signal.

TECHNICAL FIELD

The present invention relates to telecommunications, and, in particularembodiments, to an apparatus and method to configure antenna beam width.

BACKGROUND

In cross-polarized antennas systems for wireless or cellularcommunications, such as for Long Term Evolution (LTE), the antenna isdesigned to emit two cross-polarized radio frequency (RF) beams at +45°and −45° polarization respectively. Further, the two polarizations areset to the same down tilt angle, for example 8° for each of the twopolarized beams. To ensure proper multiple-input and multiple-output(MIMO) operation, multiple cross-polarized antennas need to have thesame coverage, which is significantly impacted by their down tiltangles. However, the current setup of the cross-polarized antennas, witha fixed down tilt angle of the two polarized beams, does not offer anyMIMO or beamforming functionality in the elevation dimension. There is aneed for an improved cross-polarized antennas design that providesversatile functionality for MIMO or beamforming in general, such asversatile elevation or three-dimensional coverage.

SUMMARY OF THE INVENTION

Technical advantages are generally achieved, by embodiments of thisdisclosure which describe an apparatus and method to configure antennabeam width.

In accordance with an embodiment, a method for performing polarizedtransmissions is provided. In this example, the method includesgenerating two signals, obtaining a low-beam signal and a high-beamsignal by applying different beamforming weight vectors to the twosignals, and transmitting the low-beam signal and the high-beam signalover different polarizations of an antenna array to emit a low-beamtransmission signal and a high-beam transmission signal. In thisexample, the high-beam transmission signal has a different antenna tilt,a different beam-width, and a different polarization than the low-beamtransmission signal. An apparatus for performing this method is alsoprovided.

In accordance with another embodiment, access point (AP) for performingpolarized transmissions is provided. In this example, the AP comprisesan antenna array, and a radio transmitter coupled to the antenna array.The radio transmitter is adapted to apply different beamforming weightvectors to two signals to obtain a low-beam signal and a high-beamsignal, and to transmit the low-beam signal and the high-beam signalover different polarizations of an antenna array to emit a low-beamtransmission signal and a high-beam transmission signal. In thisexample, the high-beam transmission signal has a different antenna tilt,a different beam-width, and a different polarization than the low-beamtransmission signal.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawing, in which:

FIG. 1 illustrates a diagram of an embodiment wireless communicationsnetwork;

FIG. 2 illustrates a diagram of an embodiment cross-polarized antennafor producing high-beam and low-beam transmission signals havingdifferent antenna tilts, beam-widths, and polarizations than oneanother;

FIG. 3 illustrates a diagram of a coverage scheme for embodimentlow-beam and high-beam transmissions;

FIG. 4 illustrates a diagram of an embodiment transmitter for performinglow-beam and high-beam transmissions;

FIG. 5 illustrates a diagram of another embodiment transmitter forperforming low-beam and high-beam transmissions;

FIG. 6 illustrates a flowchart of an embodiment method for performinglow-beam and high-beam transmissions;

FIG. 7 illustrates a diagram of an embodiment low-beam transmissionsignal having upper side-lobe suppression;

FIG. 8 illustrates a diagram of an embodiment high-beam transmissionsignal having lower side-lobe suppression;

FIGS. 9A-9B illustrate charts of simulation results demonstratingperformance advantages of embodiment high-beam and low-beam transmissiontechniques;

FIGS. 10A-10B illustrate charts of additional simulation resultsdemonstrating performance advantages of embodiment high-beam andlow-beam transmission techniques;

FIGS. 11A-11B illustrate charts of yet additional simulation resultsdemonstrating performance advantages of embodiment high-beam andlow-beam transmission techniques;

FIG. 12 illustrates a diagram of an embodiment computing platform; and

FIG. 13 illustrates a diagram of an embodiment communications device.

Corresponding numerals and symbols in the different figures generallyrefer to corresponding parts unless otherwise indicated. The figures aredrawn to clearly illustrate the relevant aspects of the embodiments andare not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of embodiments of this disclosure are discussed indetail below. It should be appreciated, however, that the conceptsdisclosed herein can be embodied in a wide variety of specific contexts,and that the specific embodiments discussed herein are merelyillustrative and do not serve to limit the scope of the claims. Further,it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of this disclosure as defined by the appended claims.

A cross polarized antenna system that produces high-beam and low-beamtransmission signals having different antenna beam down tilt angles anddifferent polarizations is discussed in U.S. patent application Ser. No.14/609,251 filed Jan. 29, 2015 and entitled “Apparatus and Methods forCross-Polarized Tilt Antennas,” which is incorporated by referenceherein as if reproduced in its entirety.

Aspects of this disclosure expand on that concept by using differentbeam-widths for the high-beam and low-beam transmission signals, therebyproducing high-beam and low-beam transmission signals that havedifferent antenna tilts, different beam-widths, and differentpolarizations than one another. The high-beam transmission signal andthe low-beam transmission signal may have orthogonal polarizations. Forexample, the high-beam transmission signal and the low-beam transmissionsignal may be linearly polarized signals having differentelectromagnetic field (E-field) polarization angles with respect to they-axis, e.g., +/− forty-five degrees with respect to a verticallypolarized wave. As another example, the high-beam transmission signalmay be a vertically polarized signal, and the low-beam transmissionsignal may be a horizontally polarized signal, or vice-versa. In otherexamples, the high-beam and low-beam transmission signals may becircularly or elliptically polarized signals having right-hand andleft-hand electromagnetic field (E-field) polarizations. In addition tohaving orthogonal polarizations, the low-beam transmission signal mayhave a greater antenna beam down-tilt angle, and a wider beam-width thanthe high-beam transmission signal. For instance, the low-beamtransmission signal may have a fourteen degree antenna beam down-tiltangle and an eight degree beam-width, while the high-beam transmissionsignal may have an eight degree down-tilt angle and a four degreebeam-width. Other combinations are also possible. Additional performanceenhancements may be achieved by performing upper side-lobe suppressionon the low-beam signal, and lower side-lobe suppression on the high-beamsignal. In particular, performing side-lobe suppression on therespective high-beam and low-beam transmission signals may providesignificant performance advantages in multi-usermultiple-input-multiple-output (MU-MIMO) implementations. Also, the highbeam and low beam pattern may be optimized for different targets, e.g.the high beam may be optimized for maximum gain and directivity, whilethe low beam may be optimized for minimum interference with the highbeam. These and other aspects are described in greater detail below.

FIG. 1 illustrates a network 100 for communicating data. The network 100comprises a base station 110 having a coverage area 101, a plurality ofmobile devices 120, and a backhaul network 130. As shown, the basestation 110 establishes uplink (dashed line) and/or downlink (dottedline) connections with the mobile devices 120, which serve to carry datafrom the mobile devices 120 to the base station 110 and vice-versa. Datacarried over the uplink/downlink connections may include datacommunicated between the mobile devices 120, as well as datacommunicated to/from a remote-end (not shown) by way of the backhaulnetwork 130. As used herein, the term “base station” refers to anycomponent (or collection of components) configured to provide wirelessaccess to a network, such as an enhanced base station (eNB), amacro-cell, a femtocell, a Wi-Fi access point (AP), or other wirelesslyenabled devices. Base stations may provide wireless access in accordancewith one or more wireless communication protocols, e.g., long termevolution (LTE), LTE advanced (LTE-A), High Speed Packet Access (HSPA),Wi-Fi 802.11a/b/g/n/ac, etc. As used herein, the term “mobile device”refers to any component (or collection of components) capable ofestablishing a wireless connection with a base station, such as a userequipment (UE), a mobile station (STA), and other wirelessly enableddevices. In some embodiments, the network 100 may comprise various otherwireless devices, such as relays, low power nodes, etc.

Aspects of this disclosure provide techniques for producing high-beamand low-beam transmission signals that have different antenna tilts,different beam-widths, and different polarizations than one another.FIG. 2 illustrates a diagram of an embodiment cross-polarized antenna210 for producing high and low beam transmission signals. As shown, theembodiment cross-polarized antenna 210 may produce a low-beamtransmission signal 212 and a high-beam transmission signal 214. Thelow-beam transmission signal 212 has a different antenna tilt, adifferent beam-width, and a different polarization than the high-beamtransmission signal 212. In some implementations, it may be desirablefor the low-beam transmission signal 212 and the high-beam transmissionsignal 214 to have linearly orthogonal polarizations, with the low-beamtransmission signal 212 having more antenna down-tilt and a widerbeam-width than the high-beam transmission signal 214. In the exampleddepicted by FIG. 2, the low-beam transmission signal 212 comprises anegative forty-five degree polarization, a fourteen degree antennadown-tilt, and an eight degree beam-width, while the high-beamtransmission signal 214 comprises a positive forty-five degreepolarization, an eight degree antenna down-tilt, and a four degreebeam-width. Other combinations are also possible.

Notably, the low-beam transmission signal 212 and the high-beamtransmission signal 214 may have any polarization, so long as theirrespective polarizations are different than one another. For instance,the low-beam transmission signal 212 and the high-beam transmissionsignal 214 may have orthogonal polarizations, quasi-orthogonalpolarizations, or non-orthogonal polarizations with respect to oneanother. In one embodiment, the low-beam transmission signal 212 and thehigh-beam transmission signal 212 are linearly polarized signals havingdifferent electromagnetic field (E-field) polarization angles withrespect to the x-axis/y-axis. In one example (as depicted in FIG. 2),the low-beam transmission signal 212 and the high-beam transmissionsignal 214 have negative/positive forty-five degree polarization angleswith respect to the y-axis. In another example, the low-beamtransmission signal 212 and high-beam transmission signals 214 haverespective horizontal and linear polarizations, or vice versa. In otherembodiments, the low-beam transmission signal 212 and the high-beamtransmission signal 214 are circularly or elliptically polarized signalshaving different electromagnetic field (E-field) polarization angleswith respect to the x-axis and the y-axis at a given point in space andtime. For example, the low-beam transmission signal 212 and thehigh-beam transmission signal 214 may be circularly polarized signalshaving orthogonal right-hand and left-hand polarizations. As discussedherein, the y-axis corresponds to a vertically polarized wave, and thex-axis corresponds to a vertically polarized wave.

Additionally, the low-beam transmission signal 212 and the high-beamtransmission signal 214 may have any beam-width, so long as theirrespective beam-widths are different. For purposes of this disclosure,the term “beam-width” refers to an angle between negative three decibel(−3 dB) points of the main lobe of the respective transmission signal.Moreover, the phrase “different beam-widths” refers to signals that arepurposefully transmitted with different beam-widths, and should not beinterpreted to include transmission signals that incidentally havedifferent beam-widths as a result of transmitter calibration,manufacturing tolerance, etc. In one example, the beam-width of thelow-beam transmission signal 212 is at least one-degree wider than thebeam-width of the high-beam transmission signal 214. In yet anotherexample, the beam-width of the low-beam transmission signal 212 is atleast fifty percent wider than the beam-width of the high-beamtransmission signal 214. In yet another example, the beam-width of thelow-beam transmission signal 212 is at twice as wide as the beam-widthof the high-beam transmission signal 214.

Lastly, the low-beam transmission signal 212 and the high-beamtransmission signal 214 may have any antenna-tilt, so long as theirrespective antenna-tilts differ. In this disclosure, the term“antenna-tilt” refers to an angular direction in which the main-lobe ofthe transmission signal is aimed. Antenna-tilt may be achievedelectrically or mechanically. In some embodiments, the low-beamtransmission signal 212 has more antenna down-tilt than the high-beamtransmission signal 214. For example, an antenna down-tilt of thelow-beam transmission signal 212 may be at least three degrees greaterthan an antenna down-tilt of the high-beam transmission signal 214. Inanother example, the antenna down-tilt of the low-beam transmissionsignal 212 may be at least six degrees greater than an antenna down-tiltof the high-beam transmission signal 214. In other embodiments, thelow-beam transmission signal 212 has an antenna down-tilt (e.g., themain lobe is aimed below the horizontal plane), while the high-beamtransmission signal 214 has an antenna up-tilt (e.g., the main lobe isaimed above the horizontal plane). In yet other embodiments, thelow-beam transmission signal 212 has less antenna up-tilt than thehigh-beam transmission signal 214.

FIG. 3 illustrates a diagram of an embodiment coverage scheme forhigh-beam and low-beam transmission signals. The coverage areasrepresent an example of cell layout for low-beam and high-beamtransmission signals, which may be produced using different precodingmatrix indicators (PMIs).

Aspects of this disclosure provide embodiment transmitters forperforming high-beam and low-beam transmissions. FIG. 4 illustrates adiagram of an embodiment transmitter 400 for transmitting high-beam andlow-beam transmission signals. As shown, the embodiment transmitter 400includes a cross-polarized antenna 410, radio frequency (RF)transmitters 420, 425, power amplifiers (PAs) 430, 435, and duplexers(DUPs) 450, 455. The RF transmitter 420, PA 430, and DUP 450 may beadapted to produce the low-beam signal, while the RF transmitter 425, PA435, and DUP 455 may be adapted to produce the high-beam signal. Therespective low-beam signal and the high-beam signal may thereafter betransmitted over different polarizations (e.g., poles) of thecross-polarized antenna 410 to emit a low-beam transmission signal and ahigh-beam transmission signal, respectively, that have different antennatilts, beam-widths, and polarizations. While much of this disclosurediscuss performing high-beam and low-beam transmissions overcross-polarized antennas, those of ordinary skill in the art willunderstand that other types of antennas may be used to perform thehigh-beam and low-beam transmissions. For instance, vertically andhorizontally polarized antennas may be used to produce linearlypolarized orthogonal high-beam and low-beam transmission signals. Asanother example, right-hand and left-hand circularly polarized antennasmay be used to produce circularly polarized orthogonal high-beam andlow-beam transmission signals. Antennas adapted to produce ellipticallypolarized signals may also be used. In some embodiments, the high-beamand low-beam transmission signals have substantially orthogonalpolarizations. In other embodiments, the polarizations arequasi-orthogonal.

In some embodiments, a hybrid coupler may be included in a transmitterto equalize the coverage of baseband ports driving the RF transmitters,which may allow power sharing between the PAs such that each PA can bedirected at either signal. FIG. 5 illustrates a diagram of an embodimenttransmitter 500 for transmitting high-beam and low-beam transmissionsignals. As shown, the embodiment transmitter 500 includes across-polarized antenna 510, RF transmitters 520, 525, PAs 530, 535, ahybrid coupler 540, and DUPs 550, 555. The cross-polarized antenna 510,RF transmitters 520, 525, PAs 530, 535, and DUPs 550, 555 of theembodiment transmitter 500 may be substantially similar to likecomponents of the embodiment transmitter 400. The hybrid coupler 540 maybe configured to allow power sharing between the PAs 530, 535 such thatany portion of the cumulative power output of the PA can be directed ateither the low-beam signal or the high-beam signal. For example, theentire power output of the PA 535, and half the power output of the PA530, may be directed at the high-beam signal, while the other half ofthe power output of the PA 530 is directed at the low-beam signal. Thismay allow the high-beam signal to have a higher transmit power levelthan would otherwise be attainable without the power-sharing capabilityprovided by the hybrid coupler 540.

Aspects of this disclosure provide methods for transmitting high-beamand low-beam transmission signals. FIG. 6 illustrates a flowchart of anembodiment method 600 for transmitting high-beam and low-beamtransmission signals, as may be performed by a transmitter. As shown,the embodiment method 600 begins at step 610, where the transmittergenerates two signals. Thereafter, the embodiment method 600 proceeds tostep 620, where the transmitter applies different beamforming weightvectors to the two signals to obtain a low-beam signal and a high-beamsignal. The beamforming weight vectors are configured to produce signalshaving different spatial characteristics, e.g., different patterns ofconstructive/destructive interference, etc. Specifically, thebeamforming weight vectors are adapted to provide different degrees ofantenna tilt and different beam-widths. In some embodiments, thebeamforming weight vectors also provide side-lobe suppression for theresulting high-beam and low-beam signals. For example, the beamformingweight vector applied to generate the low-beam signal may provide upperside-lobe suppression, while the beamforming weight vector applied togenerate the high-beam signal may provide lower side-lobe suppression.Side-lobe suppression is discussed in greater detail below.Subsequently, the embodiment method 600 proceeds to step 630, where thetransmitter transmits the low-beam signal and the high-beam signal overdifferent polarizations of an antenna array to emit a low-beamtransmission signal and a high-beam transmission signal having differentantenna tilts, beam-widths, and polarizations.

As mentioned above, some embodiments may perform upper side-lobesuppression on the low-beam signal and lower side-lobe suppression onthe high-beam signal to reduce interference between the resultinglow-beam and high-beam transmission signals. Performing upper side-lobesuppression for the low-beam signal may suppress (e.g., reduce thetransmit power) of secondary lobe(s) of the low-beam signal having thesame elevation angle as a primary-lobe of the high-beam signal.Likewise, performing lower side-lobe suppression for the high-beamsignal may suppress secondary lobe(s) of the high-beam signal having thesame elevation angle as a primary-lobe of the low-beam signal. In someembodiments, side-lobe suppression may also suppress leading/trailingportions of the primary lobes of the low-beam and/or high-beam signalwhen the primary lobes of the respective high-beam and low-beam signalspartially overlap, as may occur when there is a relatively smalldifference in their respective antenna tilts.

FIG. 7 illustrates a diagram of an embodiment low-beam signal havingupper-side lobe suppression, and FIG. 8 illustrates a diagram of anembodiment high-beam signal having lower-side lobe suppression. Asshown, portions of the respective signals are suppressed to reduceinterference. Notably, side-lobe suppression may have substantialperformance advantages for multi-user MIMO (MU-MIMO) applications, asdemonstrated by the simulation results below.

Emitting low-beam and high-beam transmission signals having differentantenna tilts, beam-widths, polarizations offers substantial performanceadvantages. FIGS. 9A-9B illustrate charts 910, 920 of simulation resultsdemonstrating performance advantages of embodiment high-beam andlow-beam transmission techniques. Specifically, the chart 910demonstrates average throughput rates across all user for three wirelessnetworks, while the chart 920 demonstrates average throughput rates forcell-edge users in the three wireless networks. The first wirelessnetwork (WN1) utilizes transmission signals having differentpolarizations, but the same antenna tilt and beam-width, as is typicalof conventional networks. The second wireless network (WN2) utilizestransmission signals having different polarizations and differentantenna tilts, but the same beam-width, as is discussed in U.S. patentapplication Ser. No. 14/609,251. The third wireless network (WN3) is anembodiment wireless network that utilizes low-beam and high-beamtransmission signals having different polarizations, different antennatilts, and different beam-widths. As shown, WN-3 provides the bestaverage performance, as well as the best performance at the cell-edge.

The embodiment low-beam and high-beam transmission techniques alsoprovide advantages in single user (SU) MIMO (SU-MIMO) and multi-userMIMO (MU-MIMO) wireless networks. FIGS. 10A-10B illustrate charts 1010,1020 of simulation results demonstrating performance advantages ofembodiment high-beam and low-beam transmission techniques. Specifically,the chart 1010 demonstrates average throughput rates across all usersfor four MIMO wireless networks (WN4-WN7), while the chart 1020demonstrates average throughput rates for cell-edge users in the fourMIMO wireless networks. The fourth wireless network (WN4) is aconventional SU-MIMO network, and the fifth wireless network (WN5) is aconventional MU-MIMO network. The sixth wireless network (WN6) is anembodiment SU-MIMO network adapted to communicate low-beam and high-beamtransmission signals having different polarizations, different antennatilts, and different beam-widths. The seventh wireless network (WN7) isan embodiment MU-MIMO network adapted to communicate low-beam andhigh-beam transmission signals having different polarizations, differentantenna tilts, and different beam-widths. As shown, the embodimentSU-MIMO network (WN-6) provides better performance than the conventionalSU-MIMO network (WN-4) across all users, while still providingcomparable performance at the cell edge. Moreover, the embodimentSU-MIMO network (WN-7) provides better performance than the conventionalSU-MIMO network (WN-5) across all users, as well as at the cell edge.Additional performance gains may be achieved by dynamically manipulatingthe antenna patterns for the low-beam and high-beam transmissionsignals.

Notably, implementing side-lobe suppression to the low-beam andhigh-beam transmissions may further increase performance, particularlyin the context of SU-MIMO and MU-MIMO networks. FIGS. 11A-11B illustratecharts 1110, 1120 of yet additional simulation results demonstratingperformance advantages of embodiment high-beam and low-beam transmissiontechniques. The chart 1110 demonstrates average throughput rates acrossall users for four MIMO wireless networks (WN6-WN9), while the chart1020 demonstrates average throughput rates for cell-edge users in thefour MIMO wireless networks (WN6-WN9). The sixth wireless network (WN6)and the seventh wireless network (WN7) are the embodiment SU-MIMO andMU-MIMO networks, respectively, described above, i.e., WN6 and WN7 inFIGS. 10A-10B. The eight wireless network (WN8) is an embodiment SU-MIMOwireless network adapted to perform side-lobe suppression on thelow-beam and high-beam signals, and the ninth wireless network (WN9) isan embodiment MU-MIMO wireless network adapted to perform side-lobesuppression on the low-beam and high-beam signals. As shown, theembodiment SU-MIMO network (WN8) offers slightly better performance thanthe embodiment SU-MIMO networks (WN6) across all user, while providingsubstantially the same performance at the cell edge. Additionally, itcan be seen that the embodiment MU-MIMO network (WN9) offerssignificantly better performance than the embodiment MU-MIMO networks(WN7) both across all users and at the cell edge. Notably, the advantagederived from side-lobe suppression in MU-MIMO is more pronounced at thecell edge, than at the cell center.

Aspects of this disclosure may allow for beam steering when using twotransmission streams and a single column of antenna resources, as wellas using the standard release eight two transmit-stream (2T) codebook.Additional capacity increases may be derived through beam shaping.

FIG. 12 illustrates a block diagram of a processing system that may beused for implementing the devices and methods disclosed herein. In anembodiment, the processing system is included in an access point adaptedto transmit the high-beam and low-beam transmission signals discussedabove. Specific devices may utilize all of the components shown, or onlya subset of the components, and levels of integration may vary fromdevice to device. Furthermore, a device may contain multiple instancesof a component, such as multiple processing units, processors, memories,transmitters, receivers, etc. The processing system may comprise aprocessing unit equipped with one or more input/output devices, such asa speaker, microphone, mouse, touchscreen, keypad, keyboard, printer,display, and the like. The processing unit may include a centralprocessing unit (CPU), memory, a mass storage device, a video adapter,and an I/O interface connected to a bus.

The bus may be one or more of any type of several bus architecturesincluding a memory bus or memory controller, a peripheral bus, videobus, or the like. The CPU may comprise any type of electronic dataprocessor. The memory may comprise any type of system memory such asstatic random access memory (SRAM), dynamic random access memory (DRAM),synchronous DRAM (SDRAM), read-only memory (ROM), a combination thereof,or the like. In an embodiment, the memory may include ROM for use atboot-up, and DRAM for program and data storage for use while executingprograms.

The mass storage device may comprise any type of storage deviceconfigured to store data, programs, and other information and to makethe data, programs, and other information accessible via the bus. Themass storage device may comprise, for example, one or more of a solidstate drive, hard disk drive, a magnetic disk drive, an optical diskdrive, or the like.

The video adapter and the I/O interface provide interfaces to coupleexternal input and output devices to the processing unit. Asillustrated, examples of input and output devices include the displaycoupled to the video adapter and the mouse/keyboard/printer coupled tothe I/O interface. Other devices may be coupled to the processing unit,and additional or fewer interface cards may be utilized. For example, aserial interface such as Universal Serial Bus (USB) (not shown) may beused to provide an interface for a printer.

The processing unit also includes one or more network interfaces, whichmay comprise wired links, such as an Ethernet cable or the like, and/orwireless links to access nodes or different networks. The networkinterface allows the processing unit to communicate with remote unitsvia the networks. For example, the network interface may providewireless communication via one or more transmitters/transmit antennasand one or more receivers/receive antennas. In an embodiment, theprocessing unit is coupled to a local-area network or a wide-areanetwork for data processing and communications with remote devices, suchas other processing units, the Internet, remote storage facilities, orthe like.

FIG. 13 illustrates a block diagram of an embodiment of a communicationsdevice 1300, which may correspond to an access point adapted to transmitthe high-beam and low-beam transmission signals discussed above. In anembodiment, the communications device 1300 is an access point adapted toperform high-beam and low-beam transmissions having different antennatilts, beam-widths, polarizations than one another. The communicationsdevice 1300 may include a processor 1304, a memory 1306, a plurality ofinterfaces 1310, 1312, 1314, which may (or may not) be arranged as shownin FIG. 13. The processor 1304 may be any component capable ofperforming computations and/or other processing related tasks, and thememory 1306 may be any component capable of storing programming and/orinstructions for the processor 1304. The interfaces 1310, 1312, 1314 maybe any component or collection of components that allows thecommunications device 1300 to communicate with another device.

Although the description has been described in detail, it should beunderstood that various changes, substitutions and alterations can bemade without departing from the spirit and scope of this disclosure asdefined by the appended claims. Moreover, the scope of the disclosure isnot intended to be limited to the particular embodiments describedherein, as one of ordinary skill in the art will readily appreciate fromthis disclosure that processes, machines, manufacture, compositions ofmatter, means, methods, or steps, presently existing or later to bedeveloped, may perform substantially the same function or achievesubstantially the same result as the corresponding embodiments describedherein. Accordingly, the appended claims are intended to include withintheir scope such processes, machines, manufacture, compositions ofmatter, means, methods, or steps.

What is claimed is:
 1. A method comprising: generating two signals;obtaining a low-beam signal and a high-beam signal by applying differentbeamforming weight vectors to the two signals; and transmitting, by anaccess point, the low-beam signal and the high-beam signal overdifferent polarizations of an antenna array to emit a low-beamtransmission signal and a high-beam transmission signal, wherein thehigh-beam transmission signal has a different antenna tilt, a differentbeam-width, and a different polarization than the low-beam transmissionsignal.
 2. The method of claim 1, wherein the low-beam transmissionsignal has more antenna down-tilt and a wider beam-width than thehigh-beam transmission signal.
 3. The method of claim 2, wherein abeam-width of the low-beam transmission signal comprises an anglebetween negative three decibel (−3 dB) points of the main lobe of thelow-beam transmission signal, and wherein a beam-width of the high-beamtransmission signal comprises an angle between −3 dB points of the mainlobe of the low-beam transmission signal.
 4. The method of claim 2,wherein the low-beam transmission signal and the high-beam transmissionsignal are linearly polarized signals having different electromagneticfield (E-field) polarization angles with respect to the y-axis, they-axis corresponding to a vertically polarized wave.
 5. The method ofclaim 4, wherein the low-beam transmission signal and the high-beamtransmission signal have orthogonal E-field polarization angles.
 6. Themethod of claim 5, wherein the high-beam transmission signal comprises aforty-five degree E-field angle with respect to the y-axis, and thelow-beam transmission signal comprises a negative forty-five degreeE-field angle with respect to the y-axis, or wherein the high-beamtransmission signal comprises a negative forty-five degree E-field anglewith respect to the y-axis, and the low-beam transmission signalcomprises a forty-five degree E-field angle with respect to the y-axis.7. The method of claim 5, wherein the high-beam transmission signalcomprises a vertically polarized signal, and the low-beam transmissionsignal comprises a horizontally polarized signal, or wherein thehigh-beam transmission signal comprises a horizontally polarized signal,and the low-beam transmission signal comprises a vertically polarizedsignal.
 8. The method of claim 4, wherein a beam-width angle of thelow-beam transmission signal is at least fifty percent greater than abeam-width angle of the high-beam transmission signal.
 9. The method ofclaim 8, wherein the beam-width angle of the low-beam transmissionsignal is at least twice as wide as the beam-width angle of thehigh-beam transmission signal.
 10. The method of claim 4, wherein anantenna down-tilt of the low-beam transmission signal is at least threedegrees greater than an antenna down-tilt of the high-beam transmissionsignal.
 11. The method of claim 10, wherein the antenna down-tilt of thelow-beam transmission signal is at least six degrees greater than theantenna down-tilt of the high-beam transmission signal.
 12. The methodof claim 1, wherein the high-beam transmission signal comprises aforty-five degree electromagnetic field (E-field) polarization anglewith respect to the y-axis, an eight degree antenna down tilt, and afour degree beam-width, and wherein the low-beam transmission signalcomprises a negative forty-five degree electromagnetic field (E-field)polarization angle with respect to the y-axis, an eight degree antennadown tilt, and an eight degree beam-width, the y-axis corresponding to avertically polarized wave.
 13. The method of claim 1, wherein thelow-beam transmission signal and the high-beam transmission signal arecircularly or elliptically polarized signals having differentelectromagnetic field (E-field) polarization angles with respect to thex-axis and the y-axis at a given point in space and time, the y-axiscorresponding to a vertically polarized wave, and the x-axiscorresponding to a horizontally polarized wave.
 14. The method of claim1, wherein obtaining the low-beam signal and the high-beam signal byapplying different beamforming weight vectors to the two signalscomprises: obtaining the low-beam signal by applying a first beamformingweight vector to a first component signal; and obtaining the high-beamsignal by applying a second beamforming weight vector to a secondcomponent signal, wherein the first beamforming weight vector providesupper side-lobe suppression for the low-beam signal, and wherein thesecond beamforming weight vector provides lower side-lobe suppressionfor the high-beam signal.
 15. The method of claim 14, wherein the firstbeamforming weight vector provides upper side-lobe suppression for thelow-beam signal by suppressing a secondary lobe of the low-beam signalhaving the same elevation angle as a primary-lobe of the high-beamsignal, and wherein the second beamforming weight vector provides lowerside-lobe suppression for the high-beam signal by suppressing asecondary lobe of the high-beam signal having the same elevation angleas a primary-lobe of the low-beam signal.
 16. The method of claim 14,wherein transmitting the low-beam signal and the high-beam signal overdifferent polarizations of the antenna array to emit a low-beamtransmission signal and a high-beam transmission signal comprises:transmitting a single-user multiple-input-multiple-output (SU-MIMO)signal over the antenna array.
 17. The method of claim 14, whereintransmitting the low-beam signal and the high-beam signal over differentpolarizations of the antenna array to emit a low-beam transmissionsignal and a high-beam transmission signal comprises: transmitting amulti-user multiple-input-multiple-output (MU-MIMO) signal over theantenna array, the MU-MIMO signal transporting a first data packet tothe first user equipment (UE) via the low-beam transmission signal and asecond data packet to a second UE via the high-beam transmission signal,the first data packet and the second data packet being carried over thesame time-frequency resources via the low-beam transmission signal andthe high-beam transmission signal, respectively.
 18. An access point(AP) in a wireless network, the AP comprising: an antenna array; and aradio transmitter coupled to the antenna array, wherein the radiotransmitter is configured to apply different beamforming weight vectorsto two signals to obtain a low-beam signal and a high-beam signal, andto transmit the low-beam signal and the high-beam signal over differentpolarizations of an antenna array to emit a low-beam transmission signaland a high-beam transmission signal, wherein the high-beam transmissionsignal has a different antenna tilt, a different beam-width, and adifferent polarization than the low-beam transmission signal.
 19. The APof claim 18, wherein the low-beam transmission signal has more antennadown-tilt and a wider beam-width than the high-beam transmission signal.20. The AP of claim 18, wherein the radio transmitter is configured toapply different beamforming weight vectors to the two signals to obtainthe low-beam signal and the high-beam signal by: applying a firstbeamforming weight vector to a first component signal to obtain thelow-beam signal, wherein the first beamforming weight vector providesupper side-lobe suppression for the low-beam signal by suppressing asecondary lobe of the low-beam signal having the same elevation angle asa primary-lobe of the high-beam signal; and applying a secondbeamforming weight vector to a second component signal to obtain thehigh-beam signal, wherein the second beamforming weight vector provideslower side-lobe suppression for the high-beam signal by suppressing asecondary lobe of the high-beam signal having the same elevation angleas a primary-lobe of the low-beam signal.